velocity model for testing travel_time_new.m
remark: 1:Corad discon.; 2: Moho discon.
no   top-depth  P(km/s)  S(km/s) remark
1     0        5.71           3.40    0
2     8        5.71           3.40    0
3     16       6.53           3.77    1
4     30       6.53           3.77    0
5     40       6.53           3.77    2
6     50       6.53           3.77    0
7     64       5.71           3.40    0
8     72       5.71           3.40    0
9     80       7.97           4.45    0